Although the oscillating tools will do a good job on sanding and scraping in tight areas the most exciting is cutting. This is where the tool really saves time and aggravation. Some of the more common applications are: cutting the bottom of the door casing for the new tile or wood flooring, cutting moulding to fit in a cabinet or heat vent, plunge cut flooring for a vent, plunge cut rotting wood out of exterior siding, taking down cabinets, taking out windows, and any scenario where you cannot safely get a bigger tool to do the job or it requires several hand tools and a lot of time.
After you get comfortable with your oscillating power tool it becomes the first one you reach for when a project arises. But which blade do you reach for and why? The whole evolution of blades for oscillating tools has not been so much research and development as it has been trial and error. First were the small diameter HSS, high speed steel, blades made to cut off a cast. These blades had small triangular teeth with no hook or set and the small diameter meant the stroke was very short. There was enough action to cut the ridgid cast but the skin would just kind of wiggle with the oscillating action. This is where many people get the idea that this tool will not cut you. Depending on the blade it can cut skin very nicely.
The longer blades you see today came about as people wanted to cut deeper and faster such as around a door jamb or into a wall stud. The further you get away from tool shaft the greater the length of the arc being made by the tool. So now you reach for one of the long blades. Do you need a narrow blade or do you need a wide blade? Do you need long teeth or short teeth? Do you need a wood blade or a wood/metal blade?
Narrow-vs-Wide: Narrow is about 1 1/4" or less and wide will be in the 2 1/2" range. If you plan on doing any plunge cutting at all go for the narrow. The wide works well for jambs and long ceiling cuts but the wide tips are hard to control in tight areas. If you have to pick one take the narrow blade. It's more versatile.
Long Teeth-vs-Short Teeth: In the beginning the idea was to copy handsaws and most people used the Japanese style pull saw for cutting dowels and door jambs. It was fast and clean. This was transferred to the oscillating power tool and although very fast cutting, the long teeth were prone to breakage when hitting hard material or getting buried in the cut. The progression then went to shorter more durable bandsaw blade type teeth. A nice clean cut and because of the speed of the blade, plenty aggressive. So in summation, for a cleaner cut choose a shorter tooth pattern. The shorter teeth also make it easier to control when beginning the cut.
Wood-vs-Wood/Metal: Now you have the blade you like with a tooth pattern that gives you a good cut, then you hit a nail. This is when you find out how much the replacement blade is going to cost. At this point you are about as hot as the blade that bit into the nail. Enter the wood/metal blade. It will have either hacksaw type teeth or a blended steel called bimetal to have the toughness to take care of the nail. If you plan on encountering nails or you are doing any type of demolition work always choose the bimetal blade. Even though the blade is tougher than the others, technique becomes even more important if you want to make the blade last. When you are cutting into the wood and the sound changes, you have hit a nail. Back off just a second and let the blade breath. Try to use the all of the teeth to cut the nail and spread out the heat. With a good blade and a good technique you should get more life out of the blade. Just a final note on Metal. When the blade says metal you are generally looking at nails and light gauge steel about 1/8" or less. This will vary on the quality of your blade. If you hit a hardened screw or anything stainless steel all bets are off.
Closing Thoughts: There is a learning curve when using oscillating power tools. Part of the learning is finding out what the replacement blades cost and where to get them. With the proliferation of new oscillating tools there has come the need for a blade to fit many brands and to find out a way to make others' blades fit your tool. As a manufacturer of tools and accessories Bosch has chosen a mounting adapter to put their blades on all tools. Another company, Imperial Blades has chosen to be just in the accessory business and manufactures a universal fitting blade for several brands of oscillating tools. This has led to some less expensive blades that out perform the originals.
Next time: What is the best oscillating tool? What are my choices? What is the best tool for me?